Earlier quoted context omitted.
No. I try not to be so absolute online, but, No. The contract can be ignored. How's he going to fight it? He's been working for free and he's broke. He has more important things to worry about like eating. So a crappy lawyer takes his case on a 30% contingency. It's still an uphill road until he might somehow get something. Never work for free.
My last interns had a salary of 13€/hr gross (I´m based in Munich). Working 20 hrs a week is enough to pay the rent and buy beer. In the remaining 20 hrs you could still be the unpaid CTO/CFO/CEO of any startup.
Shit, can I intern remotely for you?